Method and apparatus of using a relay station to assist processing of requests from user ends

ABSTRACT

A method uses a relay station to assist processing of requests from user ends. The relay station acquires and monitors channel resource information received from a base station. Upon receiving a request from the UEs via the channel resource, the relay station sends the request received to the base station if it detects no response from the base station to the request. An apparatus uses a relay station to assist processing of requests from UEs. A channel resource acquisition unit acquires channel resource information from the base station. A user monitoring unit monitors the channel resource acquired by the channel resource acquisition unit and for receiving requests sent from the UEs. A base station monitoring unit monitors response from the base station to the requests upon receiving the requests sent from the UEs. A transmitting unit sends the request to the base station when no response from the base station to the request is detected.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and hereby claims priority to PCTApplication No. PCT/EP2007/061483 filed on Oct. 25, 2007 and ChineseApplication No. 200610137449.8 filed on Oct. 25, 2006, the contents ofwhich are hereby incorporated by reference.

BACKGROUND

The present invention relates to a method and apparatus of using a relaystation to assist processing of requests from user ends (UEs).

In a cellular mobile radio communication system, when a base station hasa very high covering capability and very large coverage, there may bethe following problem: when a user end is at the edge of the coverage ofthe base station, the signal received by the base station from the userend will have a poor quality due to relatively low transmitting power ofthe user end and even worse the signal sent from the user end cannot bereceived properly.

A solution to this problem is to add a relay station (RS) in the areacovered by the system. By adding a relay station in the radio cellularsystem to develop a multi-hopping capability, it will not only extendthe covering area of the system and cell capability but also will havesuch advantages as reduced transmitting power of user ends andprevention of serious shadow areas. The solution of adding a relaystation in a cellular mobile radio communication system has been widelyadopted in the art and FIG. 1 is a diagram illustrating the architectureof a cellular mobile radio communication system with a relay station.

When the relay station is added to the cellular system, an overallplanning of the system can be made as well. A feasible solution is tobuild a cellular system controlled by a base station. The concept isthat the base station sends signaling to all user ends and responds torequests sent from individual user ends. To do this, how the relaystation is used to assist end users and to forward the uplink requestsof the end users to the base station is a significant challenge.Recently, there is emerging attention to how a relay station can beadded to a cellular mobile radio communication system and studies of howthe relay station can be used to forward the uplink requests from theuser ends have started.

A method for using a relay station to forward uplink requests of endusers in a cellular mobile radio communication system is that the relaystation will not process the uplink requests received from the user endsbut will immediately send the uplink requests received to the basestation upon receipt.

The shortcoming of this method is that when the relay station receives alarge number of uplink requests from the user ends, the need ofimmediate forwarding of all uplink requests received to the base stationwill result in forwarding of large number of messages at the same time,which will greatly increase the load on the relay station. In addition,the direct forwarding of uplink requests by the relay station willgreatly increase the frequency at which the radio resources between therelay station and the base station are used, leading to waste of systemradio resources, in particular when there are a large number of relaystations in the coverage of the base station, which may even exhaust theradio resources.

SUMMARY

In view of these, one potential object is to provide a method andapparatus of using relay stations in a cellular mobile radiocommunication system to assist processing of requests from user ends.This will not only reduce the operation load on the relay stations, andthus saving in system radio resources, but also will reduce operationload on the base station, cut the system response time and furtherimprove system performance and efficiency through the assistance thatcan be provided by the relay stations to the base station.

Therefore, the inventors propose the following technical solution:

-   a method of using a relay station to assist processing of requests    from user ends, comprising:-   relay stations acquiring channel resource information from the base    station and monitoring the channel resource;-   upon receiving a request sent from a UE via the channel resource,    the relay station sending the received request to the base station    if it detects no response from the base station to the request;-   wherein the relay station determines whether the base station    responds to the request using the following steps:-   the relay station starts the timer upon receiving the request and    monitors whether the base station responds to the request; if the    base station does not respond to the request within a preset time,    the relay station determines that the base station does not respond    to the request;-   wherein the base station sets the preset time and notifies the relay    station;-   wherein the base station sets the preset time based on its    capability of directly covering the area in the vicinity of the    relay station and the preset time is smaller if the base station's    coverage capability is greater;-   wherein the base station sets the preset time based on the radio    resources available for communication between itself and the relay    station and the preset time is smaller if there are more radio    resources;-   wherein the base station sets the preset time based on the requested    responding time and the preset time is smaller if the requested    responding time is shorter;-   wherein the base station sets the preset time based on its    processing capability and load and the preset time is smaller if the    base station has a greater processing capability or a smaller load;-   wherein the base station sets the preset time based on the    processing capability and the load of the relay station and the    preset time is smaller if the relay station has a greater processing    capability or a smaller load;-   wherein the relay station determines whether the base station    responds to the request using the following steps:-   the relay station determines that the base station responds to the    request if it detects a response from the base station to the    request or detects a preset indication message sent from the base    station; otherwise, the relay station determines that the base    station does not respond to the request;-   wherein the relay station acquires the channel resource information    from the base station using the following steps:-   the base station sends the channel resources that it allocates to    the UE through a broadcast message;-   the relay station receives the broadcast message and acquires the    channel resource information of the UE;-   wherein the steps further comprise:-   upon receiving the request from the UE, the relay station measures    transmitting parameters of the UE and sends the acquired    transmitting parameters along with the request to the base station;-   wherein the transmitting parameters of the UE comprise at least one    of transmitting power, carrier frequency and time-slot information.

Based on the method described above, the inventors propose an apparatusof using relay stations to assist processing of requests from user ends,comprising:

-   a channel resource acquisition unit for acquiring channel resource    information from a base station;-   a user monitoring unit for monitoring the channel resource acquired    by the channel resource acquisition unit and for receiving requests    sent from the UE;-   a base station monitoring unit for monitoring responses from the    base station to the requests once the requests are received from the    UE;-   a transmitting unit for sending the requests to the base station if    no response from the base station to the requests is detected;-   wherein the base station monitoring unit comprises a timer unit, a    monitoring unit and a notifying unit:-   the timer unit is used to start clocking once the user monitoring    unit receives a request from a UE and to stop clocking when the    monitoring unit detects a response from the base station to the    request or when the preset time is out;-   the monitoring unit is used to monitor whether the base station    responds to the request once the timer unit starts clocking;-   the notifying unit is used to monitor both the timer unit and the    monitoring unit and to notify the transmitting unit to send the    request if the monitoring unit does not detect a response from the    base station within the preset time;-   wherein the base station sets the preset time and notifies the timer    unit;-   wherein the monitoring unit comprises:-   a response monitoring unit for monitoring a response from the base    station to the request;-   a message monitoring unit for monitoring a preset indication message    sent from the base station;-   a determining unit for monitoring both the response monitoring unit    and the message monitoring unit and determining that the base    station responds to the request if the response monitoring unit    detects a response from the base station to the request or the    message monitoring unit detects a preset indication message sent    from the base station; and otherwise, determining that the base    station does not respond to the request and sending the    determination result to the notifying unit;-   Wherein the apparatus further comprises:-   a measuring unit for measuring the transmitting parameters of the UE    when the user monitoring unit receives the request from the UE;-   an adding unit for notifying the transmitting unit of the    transmitting parameters acquired by the measuring unit to allow the    transmitting unit to send the transmitting parameters along with the    request to the base station.

The relay station will monitor the channel resource after it receivesthe channel resource information from the base station. When the relaystation receives a request from a user end via the channel resource, itwill monitor whether the base station responds to the request. If therelay station does not detect a response from the base station to therequest, it will send the received request to the base station. Fromthis we can see that the relay station does not immediately forward theuplink request to the base station upon receipt of the request but willmonitor the base station instead. Only when the relay station does notdetect a response message sent from the base station, indicating thebase station has not received the uplink request from the UE, will itforward the request to the base station. In this way, the operation loadof the relay station is reduced and more importantly the system radioresources are saved. The inventors propose a method and apparatuswherein the relay station measures the transmitting parameters of the UEwhile receiving the request from the UE and will send the transmittingparameters along with the request to the base station. As a result, thesystem radio resources are saved and the relay stations can be used toassist the base station to reduce the operation load of the basestation, cut the system responding time and further improve the systemperformance and efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of the present invention willbecome more apparent and more readily appreciated from the followingdescription of the preferred embodiments, taken in conjunction with theaccompanying drawings of which:

FIG. 1 is a diagram illustrating the architecture of a cellular mobileradio communication system with relay stations;

FIG. 2 is a flowchart showing an embodiment of the proposed method;

FIG. 3 is a flowchart illustrating how the relay station determineswhether the response message is received from the base station withinthe preset time;

FIG. 4 is a diagram illustrating a proposed apparatus;

FIG. 5 is a diagram illustrating another proposed apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to like elementsthroughout.

The soul of the proposals lies in the concept that when the relaystation receives a request from a user end through the channel resourceit monitors, it will not send the request to the base stationimmediately but will wait for a response message from the base station.When the relay station receives the response message to the request fromthe base station within the preset time, it realizes the base stationhas received the request and will not send the request to the basestation again. If the relay station does not receive a response messageto the request from the base station within the preset time, it realizesthat the base station has not received the request and will send therequest to the base station.

The method will be further described in combination with embodiments andFIG. 2 is a flowchart of the method.

After allocating the uplink channel resource to the UE in step 201, thebase station sends the uplink channel resource it allocates through abroadcast message. The relay station will be notified of the uplinkchannel resources to be used by individual user ends through broadcastmessages sent from the base station and will monitor the uplink channelresources notified by the base station.

The base station allocates the uplink channel resource to a user end andthe user end is notified of the uplink channel resource allocated to itand will send a relevant uplink request through the relevant channelresource. The relay station is able to receive the uplink request sentfrom the user end by monitoring the uplink channel resource notified bythe base station.

Wherein the uplink channel resources comprise time-slot resource,carrier resource and modulation/coding methods.

When the user end sends the uplink request to the base station throughthe uplink channel resource allocated by the base station, as in step202, the uplink request will be received by the relay station.

The relay station does not send the uplink request to the base stationimmediately upon receipt of the uplink request of the user end from theuplink channel resource that it monitors but will start the timer andmonitor the response of the base station as in step 203. The relaystation decides whether or not to send the uplink request received tothe base station based on how the base station responds.

Once the timer is started, the relay station will determine whether aresponse message is sent from the base station within the preset timeT_(help) as in step 204, that is, whether a response message to therequest is received from the base station. If, within the preset timeT_(help), a response to the uplink request sent from the user end isreceived from the base station, indicating the base station has receivedthe uplink request sent from the user end, the relay station willexecute step 205, that is, does not send the uplink request to the basestation again. If, within the preset time T_(help), no response to theuplink request sent from the user end is received from the base station,indicating the base station has received the uplink request sent fromthe user end, the relay station will execute step 206, that is, sendsthe uplink request to the base station.

A method for the relay station to determine whether response from thebase station to the request is received with the preset time T_(help) isshown in FIG. 3.

At step 301, the relay station will start the timer and monitor theresponse message from the base station upon receiving the request fromthe user end, and at step 302, will enquire about whether a response tothe request is received from the base station, and if yes, at step 304,will stop the timer and determine that the base station responds to therequest, indicating the base station has received the request.Otherwise, at step 303, the relay station will determine whether thepreset time T_(help) is out, and if yes, at step 305, will stop thetimer and determine that the base station has not responded to therequest, indicating the base station has not received the request;otherwise, will continue to execute step 302.

In actual operation, the base station's response to the request of theuser end may some time be delayed, leading to same delay in the clockingof the relay station, and thus increasing the clocking load at the relaystation site. To reduce the load on the relay, the base station mayimmediately send an express indication message upon receiving therequest from the user end to notify the relay station that the requestis received. Once the indication message is received from the basestation within the preset time, the relay station will immediately stopthe timer and realize the base station has received the request from theuser end, thus reducing the time delay and hence reduced clocking loadof the relay station. The base station may determine whether or not tosend the express indication message when appropriate, and for the relaystation, it can be notified of the receipt of the request from the basestation by the base station when it receives the express indicationmessage or response from the base station.

In the method described above, the relay station simply sends the uplinkrequest received to the base station meaning that the base station onlyforwards the uplink request. In real operation context, the relaystation may also measure the transmitting parameters, includingtransmitting power, carrier frequency and time-slot information, of theuser end when it receives the uplink request from the user end. When therelay station sends the uplink request to the base station, thetransmitting parameters of the user end will be sent along with theuplink request. This allows the base station to obtain both the requestand transmitting parameters of the user end, reducing the systemresponse time and load of the base station, and in turn improving thesystem performance and efficiency.

After the method is described in detail, the following will furtherexplain how the method is applied on various occasions.

The method may be used in the initial ranging process in anIEEE802.16-based cellular mobile radio communication system.

When the user end sends a code division multiple access (CDMA) code overthe initial ranging channel resource determined by the base station, theinitial ranging program starts. The base station uses thecharacteristics of the CDMA code for content resolution. When the basestation successfully resolves the initial ranging request of the userend, it allocates the uplink bandwidth for the user end, indicatingsuccessful CDMA code resolution, and proceeds to the network accessprogram at the next step. However, when the user end is at adisadvantageous location, for example a shadow attenuation area, thebase station may not be able to receive the CDMA code sent from the userend, and will not respond to the initial ranging request and will notperform the subsequent operations.

The initial ranging channel resource will be monitored by the relaystation once allocated by the base station. When the user end sends theCDMA code over the initial ranging channel resource determined by thebase station, the relay station can receive the CDMA code sent from theuser end through the ranging channel resource and will resolve thecontent of the CDMA code even if the base station has not received theCDMA code. The relay station will monitor the response of the basestation to the initial ranging request. If the relay station finds thatthe request is successfully processed by the base station, it willremain silent and if not, it will send the CDMA code and its resolvedcontent to the base station. The base station will choose and decide arelay station suitable for executing the initial ranging program for theparticular user end according to the information received from the relaystation. Similarly, the method may also be used in periodic rangingprocess, which will not repeated herein.

The method may be used in the user end network access process in anIEEE802.16-based cellular mobile radio communication system.

An important process of user end network access is that the user endadjust the radio transmitting parameters, such as transmitting power,carrier frequency and time-slot parameter, as required by the basestation. If the process of adjusting the parameters for the user end canbe made in a shorter time, the processing time of network process forthe end user will be reduced and hence faster network access for theuser end. The method can help to quicken the process of adjustingparameters by the user end, and in turn reduce the processing time ofnetwork access for the user end.

When the user end attempts to access the network, it first monitors thebroadcast message from the base station to obtain information about thechannel resource available. The user end sends a network access requestto the base station through the relevant channel resource. If the basestation can receive the request, it will respond to the request and senda response message carrying the parameter adjustment command to the userend. Upon receiving the response message, the end user will adjust therelated parameters according to the parameter adjustment command carriedby the message. Then the user end will again send a network access tothe base station and continue to wait for a response message. Theprocess is repeated until the transmitting parameters of the user endrequesting the network access are properly adjusted and the networkaccess program proceeds to the next step. However, when the user end isat a disadvantageous location, e.g. shadow attenuation area, the basestation may not be able to receive the network access request from theuser end and will not respond to the network access request. As aresult, it cannot perform the subsequent operations, leading to delayednetwork access for the user end.

According to the method, the initial ranging channel resource will bemonitored by the relay station once allocated by the base station. Whenthe user end attempts to access a certain base station, it first obtainsinformation about available channel resource from a broadcast messagesent from the base station and then uses the channel resource allocatedby the base station to send a network access request. When the user endsends the network access request to the base station, the relay stationwill receive the network access request through the channel resourcethat it monitors and measure the transmitting parameters of the user endeven if the base station has not received the network access requestfrom the user end. The relay station will monitor the response of thebase station to the network access request. If the relay station findsthe network access request has been successfully processed by the basestation, it will remain silent and if not, it will send the transmittingparameter of the user end along with network access request to the basestation. The base station will respond to the network access request andobtain the adjustment parameters according to the transmittingparameters of the user end sent from the relay station and then send aresponse message carrying the adjustment parameters to the user end. Itcan be seen that the method can reduce the responding time of the basestation and quicken the process of adjusting parameters by the user endand thus reduce the time of network access for the user end.

The preset time T_(help) is vital to the solution and T_(help) can beused to control how the relay station handles uplink requests. Forexample:

When T_(help)=0 and if an uplink request is received by the relaystation, the request will be sent to the base station immediately. If itis necessary to use the relay station to remove any shadow attenuationareas in the system or the base station has sufficient radio resources,the setting of T_(help)=0 can be used.

When T_(help)=∞, the relay station will not be able to send the uplinkrequest received to the base station and if it is certain that the basestation can handle all uplink requests with its coverage, the setting ofT_(help)=∞ can be used.

When setting T_(help), a plurality of factors should be considered,including the area in the vicinity of the relay station that can bedirectly covered by the base station, the radio resources available forcommunication between the base station and relay station, delayrequirement for uplink request processing and operation load on the basestation.

The base station may set T_(help) dynamically as needed and notify therelay station of setting of T_(help) and the relay station will setaccording to the setting of T_(help) informed by the base station. Themethods for setting T_(help) include: the base station sets T_(help)according to its capability of directly covering the area neighboring onthe relay station wherein T_(help) is smaller if the coverage capabilityof the base station is greater; the base station sets T_(help) accordingthe radio resource available for communication between itself and therelay station wherein T_(help) is smaller if the available radiosresources are more; the base station sets T_(help) according to theresponding time requested wherein T_(help) is smaller if the requestedresponding time is shorter; the base station sets the preset timeT_(help) according to its own processing capability or its load whereinT_(help) is smaller if the base station has greater processingcapability or a smaller load; the base station sets T_(help) accordingto the processing capability or load of the relay station whereinT_(help) is smaller if the relay station has greater processingcapability or smaller load.

A smaller value of T_(help) will not only reduce the required respondingtime but also reduce the operation load of the relay station. However, asmaller value of T_(help) will also increase the frequency at which theradio resources are used, which in turn makes it necessary to use moreradio resources for communication between the base station and relaystation. By fine tuning the setting of T_(help), the processing ofuplink requests at the relay station can be controlled accurately.Setting T_(help) to different values will allow the relay station tosend the uplink requests it receives to the base station at a differenttime delay.

Based on the methods described above, the inventors further propose anapparatus of using relay stations to assist processing of requests fromuser ends. FIG. 4 is a schematic diagram of the apparatus, whichcomprises a channel resource acquisition unit 41, a user monitoring unit42, a base station monitoring unit 43 and a transmitting unit 44,wherein the base station monitoring unit 43 comprises a timer unit 431,a monitoring unit 432 and a notifying unit 433. The monitoring unit 432comprises a response monitoring unit 4321, a message monitoring unit4322 and a determining unit 4323.

After allocating the uplink channel resource to the UE, the base stationsends the uplink channel resource it allocates through a broadcastmessage. The channel resource acquisition unit 41 acquires informationabout the uplink channel resource to be used by the end user through thebroadcast message sent from the base station. The channel resourceacquisition unit 41 notifies the user monitoring unit 42 of the uplinkchannel resource information it acquires and the user monitoring unit 42will monitor the channel resource and receive the uplink request sentfrom the user end through the channel resource, wherein the uplinkchannel resource comprises time-slot resource, carrier resource andmodulation/coding methods.

When the user end sends the uplink request to the base station throughthe uplink channel resource allocated by the base station, the uplinkrequest will be received by the user monitoring unit 42.

Upon receiving the uplink request of the user end from the uplinkchannel resource it monitors, the user monitoring unit 42 will triggerthe base station monitoring unit 43 to monitor the base station for aresponse from the base station to the uplink request. If the monitoringunit 43 does not detect a response from the base station to the request,it will notify the transmitting unit 44 of the result and thetransmitting unit 44 will send the request received from the usermonitoring unit 42 to the base station.

Upon receiving the uplink request of the user end from the uplinkchannel resource it monitors, the user monitoring unit 42 will triggerthe timer unit 431 in the base station monitoring unit 43 to startclocking. When the timer unit 431 starts clocking, the monitoring unit432 also starts to monitor whether the base station responds to therequest. The notifying unit 433 monitors both the timer unit 431 and themonitoring unit 432 and notifys the transmitting unit 44 to send theuplink request if the monitoring unit 432 does not detect a responsefrom the base station to the uplink request within the preset timeT_(help).

Wherein the base station sets the preset time T_(help) and notifies thetimer unit 431.

Wherein the monitoring unit 432 monitors the response from the basestation to the request through the monitoring unit 4321 and monitors thepreset indication message sent from the base station through the messagemonitoring unit 4322, and monitors the response monitoring unit 4321 andmessage monitoring unit 4322 through the determining unit 4323. If theresponse monitoring unit 4321 detects a response of the base station tothe request or if the message monitoring unit 4322 detects the presetindication message sent from the base station, the determining unit 4323determines that the base station responds to the request and sends thedetermination result of response by the base station to the request tothe notifying unit 433; otherwise, it determines that the base stationdoes not respond to the request.

Based on the apparatus shown in FIG. 4, the apparatus uses relaystations to assist processing of requests from user ends as shown inFIG. 5. Compared with the apparatus shown in FIG. 4, the apparatus shownin FIG. 5 has a measuring unit 51 and adding unit 52 added.

When the user monitoring unit 42 receives the request from the user end,it can measure transmitting parameters of the user end through themeasuring unit 51, which sends the transmitting parameters acquired tothe adding unit 52, which in turn sends the transmitting parametersacquired by the measuring unit 51 to the transmitting unit 44. Thetransmitting unit 44 sends the transmitting parameters along with therequest to the base station.

Compared with the existing art, the improvement is that if the relaystation does not receive a corresponding message from the base stationwithin the preset time after receiving the request from the user endthrough the channel resource it monitors, it will send the requestreceived to the base station. From this we can see that, the relaystation does not immediately forward the uplink request to the basestation upon receipt of the request but will monitor the base stationinstead. Only when the relay station does not receive a response messagesent from the base station, indicating the base station has not receivedthe uplink request from the UE, will it forward the request to the basestation. In this way, the operation load of the relay station is reducedand more importantly the system radio resources are saved. In the methodwherein the relay station measures the transmitting parameters of the UEwhile receiving the request from the UE and will send the transmittingparameters along with the request to the base station. As a result, thesystem radio resources are saved and the relay stations can be used toassist the base station to reduce the operation load of the basestation, cut the system responding time and further improve the systemperformance and efficiency.

The invention has been described in detail with particular reference topreferred embodiments thereof and examples, but it will be understoodthat variations and modifications can be effected within the spirit andscope of the invention covered by the claims which may include thephrase “at least one of A, B and C” as an alternative expression thatmeans one or more of A, B and C may be used, contrary to the holding inSuperguide v. DIRECTV, 69 USPQ2d 1865 (Fed. Cir. 2004).

The invention claimed is:
 1. A method comprising: acquiring, by a relay station, channel resource information from a base station; monitoring, by the relay station, the channel resource at the relay station; receiving, by the relay station, via the channel resource a request sent from one of the user ends; monitoring, by the relay station, a response from the base station to the request once the request is received from the user end; and sending, by the relay station, the request to the base station in response to the relay station not detecting a response from the base station to the request within a preset time.
 2. The method of claim 1, wherein the relay station determines whether the base station responds to the request by starting a timer upon receiving the request, monitoring whether the base station responds to the request and determining that the base station does not respond to the request when the base station does not respond to the request within the preset time.
 3. The method as claimed in claim 2, wherein the base station sets the preset time and notifies the relay station.
 4. The method as claimed in claim 3, wherein the base station sets the preset time based on a capability of the base station directly covering regions neighboring on the relay station, the greater the covering capability of the base station, the smaller the preset time.
 5. The method as claimed in claim 3, wherein the base station sets the preset time based on available radio resources for communication between the base station and the relay station, the preset time being smaller when there are more available radio resources.
 6. The method as claimed in claim 3, wherein the base station sets the preset time based on a requested responding time, and the preset time is smaller when the requested response time is shorter.
 7. The method as claimed in claim 3, wherein the base station sets the preset time based on a processing capability or a load of the base station, and the preset time is smaller when the base station has a greater processing capability or a smaller load.
 8. The method as claimed in claim 3, wherein the base station sets the preset time based on a processing capability or a load of the relay station, and the preset time is smaller when the relay station has a greater processing capability or a smaller load.
 9. The method as claimed in claim 2, wherein the relay station determines that the base station responds to the request when the relay station detects a response from the base station to the request or detects a preset indication message sent from the base station and determines that the base station does not respond to the request when the relay station does not detect a response from the base station to the request and does not detect a preset indication message sent from the base station.
 10. The method as claimed in claim 1, wherein the acquiring the channel resource information from the base station at the relay station includes receiving a broadcast message including channel resources that the base station allocated to the user end from the base station and acquiring the channel resource information of the user end from the broadcast message.
 11. The method as claimed claim 1, further comprising: measuring transmitting parameters of the user end at the relay station and sending the measured transmitting parameters along with the request having been received from the user end to the base station.
 12. The method as claimed in claim 11, wherein the transmitting parameters of the user end include at least one of a transmitting power, a carrier frequency and time-slot information.
 13. An apparatus comprising: a channel resource acquisition unit for acquiring channel resource information from a base station; a user monitoring unit for monitoring the channel resource information and for receiving via the channel resource a request sent from one of the user ends; a base station monitoring unit for monitoring a response from the base station to the request once the request is received from the user end; and a transmitting unit for sending the request to the base station when no response from the base station to the request is detected within a preset time.
 14. The apparatus as claimed in claim 13, wherein the base station monitoring unit comprises at least the following: a timer unit for starting clocking once a request from the user end is received and stopping clocking when the response from the base station to the request is detected or when the preset time ends; a monitoring unit for monitoring whether the base station responds to the request once the clocking has started; and a notifying unit monitoring both the timer unit and the monitoring unit and notifying the transmitting unit for sending the request when the response from the base station is not detected within the preset time.
 15. The apparatus as claimed in claim 14, wherein the apparatus is notified of the preset time by the base station.
 16. The apparatus as claimed in claim 14, wherein the monitoring unit comprises at least the following: a response monitoring unit for monitoring the response from the base station to the request; a message monitoring unit for monitoring a preset indication message sent from the base station; and a determining unit, monitoring both the response monitoring unit and the message monitoring unit, for determining that the base station responds to the request when a response from the base station to the request is detected or a preset indication message sent from the base station is detected, determining that the base station does not respond to the request when a response from the base station to the request is not detected and a preset indication message sent from the base station is not detected.
 17. The apparatus as claimed in claim 13, further comprising at least the following: a measuring unit for measuring transmitting parameters of the user end when the user the request from the user end is received; and an adding unit, notifying the transmitting unit of the transmitting parameters acquired by the measuring unit, allowing the transmitting unit to send the transmitting parameters along with the request to the base station.
 18. A method comprising: transmitting channel resource information from a base station to the relay station; monitoring, by the relay station, the channel resource at the relay station; receiving, by the relay station, via the channel resource a request sent from a user end; and receiving a request at the base station from the relay station when the relay station does not detect a response from the base station to the request within a preset time.
 19. The method of claim 18, further comprising: allocating channel resources to the user end; transmitting a broadcast message including channel information regarding the allocated channel resources from the base station.
 20. The method of claim 18, further comprising: receiving transmitting parameters of the user end measured at the relay station along with the request having been received from the user end. 